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Squeaky velvet ant - dorsal - Dasymutilla waco - female

Squeaky velvet ant - dorsal - Dasymutilla waco - Female
McKinney Roughs Nature Park, Cedar Creek, Bastrop County, Texas, USA
August 4, 2012
Size: 14mm
I found this lady running over the ground of a sparse meadow, bordered by stands of post oaks and juniper, not too far from loblolly pines. This mutillid would make cute squeaking noises every time I bothered it. It never once made motions to sting anything I pushed it with. I recorded the squeaky noises and made a wav file, but I'm not sure where to post it.

I believe this is one of the mutillids that the spiders Castianeira occidens and Castianeira descripta probably mimic.

Images of this individual: tag all
Squeaky velvet ant - dorsal - Dasymutilla waco - female Squeaky velvet ant - lateral - Dasymutilla waco - female

Dasymutilla waco
D. waco usually has the mesosoma (thorax) as broad as long, but in this specimen it looks longer than broad. The integument of the second tergite is mostly red which helps to ID this one. All other females with this coloration in Texas have the integument of the second tergite black.

Moved from Dasymutilla.

What else do I need?
Okay, I went through the UT Austin collection today looking for mutillids found in Texas having the right mesosoma proportions and having the "integument of the second tergite is mostly red." I couldn't guarantee that the setae weren't what was making the second tergite red though, as I scanned visually and didn't use a scope.

The following species all appear to meet these requirements, plus they all look like my specimen (to me):

- Pseudomethoca brazoria (TX: Live Oak Co.)
- D. chiron (TX: Keney Co.)
- D. melanippe (TX: Kenedy Co.)
- D. meracula (TX: Duval Co.)
- D. klugioides (TX: Webb Co.)
- D. waco (TX: Bastrop Co.)
- D. wileyae (TX: Bastrop Co.)
- D. zelaya (TX: Bastrop Co.)

(Note that even the D. waco specimens I looked at appeared to have the proportions I see in this specimen -- just like all the others. I did rule out a few species that had rounded thoraxes, as this one seems to have a laterally protruding anterior.)

What else should I be looking for? Thanks for your help!

Not sure what you mean
Are you looking for characters to separate all of these species, or if there are any more species to be considered?

I'm planning to create a little video with this critter, sharing the squeaky sounds it makes and giving facts about it. I'm trying to convince myself of the species so I can so ID it in the video. At the moment I don't know how you're distinguishing it from all these look-alikes.

Very cool!
In Dasymutilla waco:

-The mesosoma is as long as broad, so it's rounded instead of elongate, so 'O' vs '()' . D. zelaya is the only other one with this character.
-The second tergite has a large red macula/spot on the integument. No other female Dasymutilla with this coloration has this character in Texas.
-Also, not visible, the mandibles are tridentate in D. waco. You'd have to use a microscope to see this.

IMO, it is impossible to "convince" yourself it is D. waco without knowing how to identify the other species, and genera, you listed.

The noise mutillids make is called stridulation, created by a file on the third tergite, which is scraped on the second tergite to create the sound.

Thank you! I spent about 40 minutes comparing this specimen to specimens in the UT Austin insect collection. I only got halfway through the collection when I quit because I already had 7 species that looked like it, for all the characters I could think to look for. D. waco was one of the names I wrote down. My specialty is spiders, and I'm having trouble figuring out what the "integument of the second tergite" is. I hit a few web pages but failed to figure it out. Can you help me understand exactly where this is? Thanks so much for your help!

Happy to help, Joe
The abdomen (called the metasoma in Hymenoptera) is composed of segments called tergites and sternites. Tergites are the dorsal segments, and sternites are the ventral segments. There are typically six segments in female aculeate wasps, and seven in males. The first tergite and sternite are attached to the mesosoma (=thorax). The sting comes out between the sixth tergite and sternite. They're often abbreviated T1,T2, T3, S1, S2, etc.

So the second tergite (T2) is the very large, dorsal segment. You can see black at the top of it and the rest is mostly red.

The integument is literally the exoskeleton. So most female mutillids that have a black head and mesosoma, and a red metasoma, just have the setae (hair) red, while the integument underneath the fuzz is black. Only two species have both the setae and integument of the second tergite (T2) red. Dasymutilla waco in TX and D. nogalensis in AZ.

This mimicry group is huge in Texas (black head and mesosoma, red metasoma). At least ten species look like this in our state.

Dasymutilla quadriguttata is a great example
This species often has four yellow spots on the integument of the second tergite.

Wow. Thank you sooo much for the detailed explanation! I'll have a look next time I'm at the collection (probably Monday).

Moved from Velvet Ants.

Moved for expert attention
Moved from ID Request.

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